First published online August 31, 2004
Journal of Experimental Biology 207, 3477-3482 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01168
The role of discontinuous gas exchange in insects: the chthonic hypothesis does not hold water
Allen G. Gibbs1,* and
Robert A. Johnson2
1 Department of Ecology and Evolutionary Biology, 1041 E. Lowell Street,
University of Arizona, Tucson, AZ 85721 USA
2 School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501,
USA

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Fig. 1. Recordings of CO2 release (AiCi) and water loss
(AiiCii) from three alate female P. barbatus. Similar
recordings were obtained for mated females and foundresses.
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Fig. 2. Plots of water-loss rate vs CO2 release for the three
individuals AC shown in Fig.
1.
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Fig. 3. Ratios of respiratory water loss to CO2 release, calculated from
the slopes of plots such as those in Fig.
2. Data are means ± S.E.M.
For N values, see Table
1.
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Fig. 4. The relationship between CO2 release and water loss during a
single gas-exchange cycle. Filled symbols indicate data recorded as
CO2 release, which increased early in the cycle, including the C
(closed) and F (flutter) phases; open symbols indicate the rest of the cycle,
as CO2 release declined after reaching its peak.
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Fig. 5. (A) Metabolic rates of ants using different patterns of gas exchange.
Significant differences are indicated by the letters ac: a<b<c.
Data are means ± S.E.M. For N
values, see Table 1.
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© The Company of Biologists Ltd 2004